Methods developed for the fabrication of integrated circuits (I.C.) are now being applied to the production of microdynamic structures, see for example, the host of sensors and fabrication techniques disclosed in "Microsensors," edited by R. S. Muller et al., IEEE Electron Devices Society, 1990, ISBN 0-87942-245-9. In addition to these structures and fabrication techniques a great variety of moving micromechanical devices, such as electrostatically driven resonant bridges, motors, tweezers, and actuators are well established in the state of the art, as described in the two publications "Microdynamics," Sensors and Actuators, by R. S. Muller, A21-A23, 1-8 (1990), 5th International Conference on Solid-State Sensors and Actuators (Transducers '89) and Eurosensors III, Montreux, Switzerland, Jun. 25-30, 1989; and "Integrated Microelectromechanical Systems: A Perspective on MEMS in the '90s" by K. D. Wise, 4th IEEE Micro Electro Mechanical Systems Workshop, Nara, Japan, Jan. 30-Feb. 2, 1991, pp. 33-38.
To date, the substrate of choice for most of the contemporary fabrications has been single crystal silicon. This selection most likely has been made to permit the application of well developed silicon microfabrication techniques and, more importantly, to allow the integration of microdynamic structures and integrated circuits onto the same substrate. In this regard the article by W. Yun, W. C. Tang, and R. T. Howe, "Fabrication Technologies for Integrated Microdynamic Systems", Integrated Micro Motion Systems--Micromachining, Control, and Applications, edited by F. Harashima, Amsterdam: Elsevier Science Publishers, 1990, pp. 297-312; Proceedings of the Third Toyota Conference, Nissin, Aichi, Japan, Oct. 11-15, 1989, shows that the current state of the art provides for the sensing, computing, and actuating being done on the same chip.
The materials used in the construction of a typical micromechanical device include a single crystal substrate, a sacrificial oxide, deposited polysilicon and/or tungsten, and perhaps silicon nitride or other dielectrics and conductors. However, the use of silicon substrates restricts the magnitude of the voltages which may be applied to the electrostatic components.
Thus, a continuing need exists in the state of the art for the application of silicon-on-sapphire substrates in the fabrication of a micromotor devices to allow the application of higher voltages to the micromotors to enhance their performance.